One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,8)(9,10,14,15)(11,19,22,16)(12,17,18,13)(20,24,23,21)(2,6)(3,7)(10,15)(12,18)(16,19)(20,23)(25,26,30,31)(27,32,37,40)(28,33,38,36)(29,34,39,35)(1,3,5,7)(2,4,6,8)(10,15)(13,17)(16,19)(21,24)(26,31)(29,39)(32,40)(33,36)(1,4)(2,7)(3,6)(5,8)(9,11,14,22)(10,16,15,19)(12,23,18,20)(13,21,17,24)(25,27)(26,32)(28,34)(29,36)(30,37)(31,40)(33,39)(35,38)(9,12,14,18)(10,17,15,13)(11,20,22,23)(16,21,19,24)(25,28)(26,33)(27,35)(29,32)(30,38)(31,36)(34,37)(39,40)(9,13,14,17)(10,18,15,12)(11,21,22,24)(16,20,19,23)(25,29)(26,34)(27,36)(28,32)(30,39)(31,35)(33,37)(38,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.